State Department spokesman Philip J. Crowley resigned on Sunday amid controversy over remarks he made last week at MIT about the treatment of Army Pfc. Bradley E. Manning. At a talk on Thursday, he called the U.S. military’s treatment of Manning, who is suspected of providing classified information to WikiLeaks, “ridiculous, counter-productive, and stupid.”

Human rights groups, including Amnesty International, have expressed concern over the treatment of Manning, who has been held in solitary confinement at the Marine Corps brig in Quantico, Va., since July. Recent reports have indicated Manning is forced to strip naked every night and wear a special smock designed to prevent him from committing suicide, a practice Manning’s lawyer has called degrading.

Crowley’s remarks first came under the national spotlight when President Barack Obama was asked about the remarks during a press conference on Friday. Obama neither condemned nor condoned Crowley’s remarks, but he stated that military officials have said the treatment of Manning was appropriate and within basic standards.

Thirty-five graduate students, professors, and researchers — mostly from MIT — responded to Crowley’s resignation with an open letter to Secretary of State Hillary Rodham Clinton, expressing concern that the remarks at MIT led to his resignation. “If public officials are made to fear expressing their truthful opinions, we have laid the groundwork for ineffective, dishonest, and unresponsive governance,” the letter said.